The present invention is directed to methods of efficient sampling of dilute solutions into a mass spectrometer and more specifically to provide an interface that permits continuous introduction of a sample effluent from a liquid chromatograph into the ionization chamber of a mass spectrometer. Moreover, the mass spectrometer may be of any known type.
FIG. 1 illustrates a prior art liquid chromatograph mass spectrometer (1c/ms) interface which includes a mass spectrometer 10 with an ionizing region 11 the remainder of the mass spectrometer being typical of the quadrupole mass filter type. The liquid chromatograph effluent is placed into a cup 12 through which a moving wire 15 moves to pick up the fluid to pass it into the mass spectrometer through a first two stage vacuum lock 13 and the wire passes out through a second vacuum lock 14 it is taken up by take-up reel 16. The supply reel is located at 17. A heating voltage is applied across the points 18 and 19, to cause that portion of the moving wire 15 to vaporize the effluent carried by it. With this type of system approximately only 1% of the effluent reaches the ionization region. In addition, there is no specific heating technique for the removal of the solvent from the effluent. Further, said device cannot be used with a conventional magnetic mass spectrometer. The presence of the wire in the ion source also distorts the electric field in the quadrupole source and thereby impairs performance.